一次强沙尘暴过程中沙尘气溶胶空间分布的初步分析

利用地面观测资料分析了2008年5月25日至29日沙尘天气的发生、发展情况,利用Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations（CALIPSO）资料分析了沙尘气溶胶在传输过程中的垂直分布状况,结合HYSPLIT模式,对此次沙尘天气过程中沙尘气溶胶的传输路径做了分析。结果表明,此次沙尘天气过程是由蒙古气旋造成的,沙尘由低空急流向远方输送;地面沙尘天气主要发生在气旋和反气旋之间强烈的北风或西北风气流中;在此次沙尘天气过程中,沙尘气溶胶的退偏振比在0.10~0.38之间,沙尘主要分布在海拔2 km到4 km之间,最高可达到5 km。     

塔克拉玛干沙漠塔中地区春夏季风蚀起沙研究

利用塔克拉玛干沙漠腹地塔中地区的观测资料,对塔中地区春夏季地表土壤风蚀起沙的临界摩擦速度及其变化特征和起沙风速进行了分析研究,并计算了2008年4月19日和7月19日两次沙尘暴天气过程沙漠地表的风蚀起沙量。结果表明:塔中地区春夏季地表起沙的临界摩擦速度为0.26 m·s-1;2 m高度的临界起沙风速约为4.1 m·s-1;两次沙尘暴过程的顺风向沙粒通量和垂直尘粒通量的平均值分别为17.44×10-4 kg·m-1·s-1 、13.8×10-8 kg·m-2·s-1、164.69×10-4 kg·m-1·s-1和799.77×10-8 kg·m-2·s-1;沙尘通量的变化与风速及摩擦速度的变化具有一致性。     

新疆包古图Ⅲ号岩体岩石学和锆石SHRIMP年代学研究

野外地质观测表明,包古图Ⅲ号岩体由两部分组成（北部的Ⅲ 1和南部的Ⅲ 2）,Ⅲ 1的岩性为花岗闪长岩和石英闪长岩,Ⅲ 2的岩性为石英闪长岩、闪长岩和少量辉石闪长岩。挑选Ⅲ 1岩体中部新鲜石英闪长岩样品,测得其锆石SHRIMP年龄为(313±3）Ma。包古图Ⅰ、Ⅱ、Ⅲ 1、Ⅳ、Ⅴ号岩体具有相似的形成时间,集中在310~325 Ma,成矿作用发生在岩浆演化的晚期（316~310 Ma）。     

退化草地封育后土壤细颗粒增加机理探讨及研究展望

土壤的恢复是退化草地生态系统恢复的难点和关键。土壤细颗粒物质的增加对退化的土壤系统恢复具有重要意义,不但可以改善土壤质地、也能输入土壤养分。通过综述退化草地封育后土壤细颗粒增加的研究案例,从植物有机体的归还、植物覆盖增加及其抑制风蚀作用和截存降尘的作用分析细颗粒增加的机理;重点总结了降尘对生态系统作用的研究进展;并从降尘对退化草地封育后土壤细颗粒增加的贡献以及草地植被对降尘的截存作用两个方面做了研究展望。     

西藏札达盆地沉积物的石英砂表面特征及其环境意义

在扫描电镜下对札达盆地香孜组、古格组和托林组地层中的石英砂表面结构特征进行观察, 三个组中石英颗粒外形磨圆度均不好, 以棱角和次棱角状为主, 结合区域地质认为, 盆地的沉积物源距离盆地沉降区很近, 为盆地周围的山地。其中香孜组的上部和中部冰川砂粒表面特征明显, 认为是水体较浅冰缘区河湖相沉积环境; 香孜组下部为湖泊水体较深的冰缘区河湖相沉积环境。古格组石英砂颗粒表面具有溶蚀坑和沟, 属于低化学能的湖相沉积。托林组则表现出河流相沉积的特点。     

Spinel–quartz high temperature paragenesis in Al–Fe granulites from the Ihouhaouene area (NW Hoggar, Algeria)

The spinel–quartz-bearing Al–Fe granulites from Ihouhaouene (In Ouzzal, West Hoggar) have a migmatitic appearance with quartzo-feldspathic layers intercalated with restitic layers. These granulites are characterized by a hercynitic spinel–quartz assemblage typical of high grade terranes. The stability of the spinel–quartz assemblage is attributed to an elevation of temperature (from 800 to >1100 °C) at high pressures (10–11 kbar), followed by an isothermal decompression from 9 to 5 kbar, an evolution typical of the In Ouzzal clockwise P–T path. The Al–Fe granulites’ history can be subdivided into different successive crystallisation stages. During the first stage, the spinel–quartz assemblage formed, probably following a prograde event that also produced partial melting. During a second stage, the primary spinel–garnet–sillimanite–quartz paragenesis broke-down to give rise to the secondary assemblage. The metamorphic evolution and phase relations during this stage are shown in P–T–X pseudosections calculated for the simple FMASH system. These pseudosections show that the orthopyroxene–cordierite–spinel symplectite appeared during a high temperature decompression, as a product of destabilisation of garnet in sillimanite-free microdomains with high X_Mg values. At the same time, the spinel–quartz association broke-down into cordierite in Fe-rich microdomains. Average pressure and temperature estimates for the orthopyroxene–spinel–garnet–cordierite–quartz association are close to the thermal peak of metamorphism (1000 ± 116 °C at 6.3 ± 0.5 kbar). With decreasing temperatures garnet–sillimanite corona developed from the breakdown of the primary spinel–quartz assemblage in the Fe-rich microdomains, whereas cordierite–spinel formed at the expense of primary sillimanite and garnet in the Mg-rich microdomains.     

滇西景谷地区澜沧江沿岸早古生代构造片岩中石英脉的成因与变形

滇西景谷县澜沧江沿岸出露的下古生界内发育一套构造片岩,空间上呈NNW—SSE向展布,岩性以绢云母石英构造片岩为主。岩石发生了强烈的塑性流变,大量发育有细脉状、透镜状的石英脉。石英脉的宏观与显微构造变形特征反映其为同构造分泌结晶脉,形成机制与韧性剪切带中物质的溶解、迁移、重结晶作用密切相关。石英原生气液包裹体显微测温实验表明,石英脉形成时的温压条件为：T=500℃,p=0.498GPa,反映构造片岩的变质程度达到了中、高绿片岩相。     

黄土粉尘搬运过程的动力学物理模型

通过对黄土粉尘重力沉降过程的动力学分析,给出了黄土粉尘粒度分布的数学表达,讨论了粉尘沉积通量随搬运距离、粒径变化的物理过程,首次确定了估算粉尘搬运距离和风力强度的计算方法,为区分粉尘搬运距离和风力强度对粒度的影响及其它们在冰期间冰期中的差异提供了物理学的判别依据。分析结果表明： 1)在重力沉降作用下,粉尘沉降通量随搬运距离的变化服从几何分布,具有沉降通量随搬运距离的增加迅速减小,越粗的粉尘颗粒其沉降通量初值越大,同时下降速度也越迅速的特点; 2)如果用携粉尘气流的水平通量作代表风力强度,则粉尘搬运距离与粒度分布曲线上重力沉降部分最高点的粉尘沉降通量成反比,风力强度与该点对应粒径的平方和粉尘搬运距离成正比。因此,根据该点的粉尘沉降通量和对应粒径,可以估算粉尘的搬运距离和风力强度。根据上述理论对渭南阳郭中学S0～L1黄土－古土壤剖面进行了粉尘搬运距离和风力强度的估算： 首先,从粒度分布中提取出3个对数正态分布的独立组份; 然后利用粗粒组份的参数计算粉尘搬运距离和风力强度。分析结果表明粉尘搬运距离具有冰期近、间冰期远的特点,风力强度的变化则具有冰期弱、间冰期强的特点,LGM时段的风力强度比MIS 3阶段大,但小于全新世适宜期,而LGM时期粉尘搬运距离并未明显减小,因此,可能黄土粒度的变化并非反映了冬季风的变化,而是反映了夏季风的变化,夏季风是通过影响粉尘源区来影响粉尘粒度的变化。     

A comparison analysis of chemical composition of aerosols in the dust and non-dust periods in Beijing

Dust events occurred frequently in Beijing in recent years. In this work, 120 aerosol samples werecollected in two typical dust events (21-22 March and 15 May) and a non-dust period in Beijing fromMarch to May 2001. Samples were analyzed for major elemental components by the Proton Induced X-ray Emission (PIXE) method. Results show that the enrichment factors of crustal elements such as Mg,A1, and Ti had little differences between the dust period and the non-dust period in Beijing, while theenrichment factors of other elements that have a relation to anthropogenic emissions were very low duringthe dust period. The results derived by using multivariate factor analysis from the observation data showthat the sources such as soil dust, industry, and fuel combustion were among the major contributors tothe particles in Beijing.     

Geological structure, composition of ores and age of the Bamsk gold deposit, Amur region, Russia

The Bamsk gold-ore deposit is located in the Amur region, the Far East of Russia. It is confined to the Early Cretaceous volcanic-plutonic uplift of central type, located in the Stanov folded-clumpy Pre-Cambrian system. The deposit is presented by a series of gold-bearing quartz and carbonate-quartz vein-stringer zones. They are confined to the super-intrusive zone of the Nevachansk subvolcanic intrusion of sienite-porphyric composition. The mineralization is being controlled by zone of fractures developed in the autochthone ofthe Bamsk fault. Quartz, carbonates and sericite prevail in the composition of ores. The quantity of ore minerals doesn't exceed 1%～5%. Pyrite, chalcopyrite, galena and native gold are widely spread. Sheelite, gold and silver tellurides, sulphobismuthites, acanthite, sphalerite and cinnabar are less developed. Four stages of mineralization have been distinguished. Gold-sulphide-sulphosalt ore with tellurides of gold and silver is productive for gold. The following set of elements is typomorphic for the ores of the deposit: Au, Ag, Cu, Bi,Mo, Pb and Sb (W1, Pb1, Mo) -Cu- (Ag, Bi, Sb, Mn, W1, Pb2) form the vertical series of zoning. Rocks, enclosing the mineralization are exposed to the processes of listvenitization-beresitization. The processes of gumbeization and argillization are less manifested. The age of the gold mineralization, determined by Rb-Sr method on ore-accompanying minerals, is 130.6 Ma.